Received: from localhost (unknown [200.46.204.182])
	by postgresql.org (Postfix) with ESMTP id A06BF9F9B89
	for <pgsql-performance-postgresql.org@postgresql.org>;
	Sat,  8 Sep 2007 13:34:29 -0300 (ADT)
Received: from postgresql.org ([200.46.204.71])
	by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024)
	with ESMTP id 49870-09 for
	<pgsql-performance-postgresql.org@postgresql.org>;
	Sat,  8 Sep 2007 13:34:25 -0300 (ADT)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.5
Received: from cronos.madness.at (madness.at [217.196.146.217])
	by postgresql.org (Postfix) with ESMTP id 630A09F9B86
	for <pgsql-performance@postgresql.org>;
	Sat,  8 Sep 2007 13:34:26 -0300 (ADT)
Received: from mastermind.kaltenbrunner.cc ([83.215.233.60])
	by cronos.madness.at with esmtpsa (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32)
	(Exim 4.63) (envelope-from <stefan@kaltenbrunner.cc>)
	id 1IU3Fr-0005pn-7B; Sat, 08 Sep 2007 18:33:58 +0200
Message-ID: <46E2CEF3.1030908@kaltenbrunner.cc>
Date: Sat, 08 Sep 2007 18:33:55 +0200
From: Stefan Kaltenbrunner <stefan@kaltenbrunner.cc>
User-Agent: Icedove 1.5.0.12 (X11/20070607)
MIME-Version: 1.0
To: "Joshua D. Drake" <jd@commandprompt.com>
CC: Gregory Stark <stark@enterprisedb.com>,
	Simon Riggs <simon@2ndquadrant.com>,
	Bernd Helmle <mailings@oopsware.de>,  mfatticcioni@mbigroup.it,
	pgsql-performance@postgresql.org
Subject: Re: DRBD and Postgres: how to improve the perfomance?
References: <2C070D1C3970467FF64F6B6A@imhotep.credativ.de>
	<1189232904.4281.19.camel@ebony.site>
	<87k5r1zd52.fsf@oxford.xeocode.com>
	<46E2CAAF.50205@commandprompt.com>
In-Reply-To: <46E2CAAF.50205@commandprompt.com>
X-Enigmail-Version: 0.94.2.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Virus-Scanned: Maia Mailguard 1.0.1
X-Archive-Number: 200709/145
X-Sequence-Number: 26690

Joshua D. Drake wrote:
> Gregory Stark wrote:
>> "Simon Riggs" <simon@2ndquadrant.com> writes:
> 
>>> You're right, but the distinction is a small one. What are the chances
>>> of losing two independent servers within a few milliseconds of each
>>> other? 
>> If they're on the same power bus?
> 
> That chance is minuscule or at least should be. Of course we are
> assuming some level of conditioned power that is independent of the
> power bus, e.g; a UPS.

how is that making it different in practise ? - if both are on the same
UPS they are affectively on the same power bus ...
If the UPS fails (or the generator is not kicking in which happens way
more often than people would believe) they could still fail at the very
same time ....


Stefan